We know that trees are useful in our everyday life. They give us   1  things, such as wood, oxygen, rubber（橡胶）, medicines   2  many other things. They can also tell us a lot about our climate. The following are the reasons. If you cut   348  a tree, you can see that it has many rings. Most trees grow one new ring   4  year. Because of this, we know how old a tree is. A tree over a hundred   5  means that it has more than a hundred   6 . When the climate is dry or very cold, the trees do not grow very much and their rings   7  usually thin. When it is wet and warm, the rings
8  thicker. If the rings are suddenly very thin or suddenly very thick, it means that the 9  changed suddenly. If we look at the rings on the tree, we can learn about the climate in the past years. We can see
  10  changing today.
小题1:A．much               B．lot                 C．many        
小题2:A．so                 B．and                 C．while       
小题3:A．down               B．cross                   C．into        
小题4:A．every              B．many            C．some        
小题5:A．year old            B．old                 C．years old       
小题6:A．plants             B．rings                   C．leaves      
小题7:．A．is                B．are                 C．were        
小题8:A．are much               B．are more            C．is much     
小题9:A．day                B．year                C．climate     
小题10:A．how our climate is     B．how is our climate   C．how to our climate